1. Field of the Invention
The present invention relates to a seat slide device for use in an automotive vehicle.
2. Description of the Related Art
Conventional seat slide devices are disclosed in EPC 0,037,726 A1 published on Oct. 14, 1981 and USP 4,756,503 published on Jul. 12, 1988.
Each of the foregoing seat slide devices comprises a lower rail which is fixed to a floor of a vehicle and having a generally U-shaped channel cross-section defined by a base arm and side arms, and an upper rail which is fixed to a seat of the vehicle and having a generally inversely T-shaped channel cross-section defined by a bar and a flange. The upper rail is slidably supported on the lower rail through balls or a roller.
The balls of the former seat slide device (EPC 0,037,726 A1) are disposed between the base arm of the lower rail and the bar of the upper rail so as to contact with corner portions between the base arm and the side arms and angular portions of the bar. In the former device, ear portions which upwardly extend from ends of the bar are encircled by inward portions which inwardly fold from ends of the side arms so as to contact with the inward portions and the side arms. Play in the longitudinal direction and lateral direction of the upper rail relative to the lower rail is prevented by the contact of the balls and the contact of the ear portions.
The roller of the latter seat slide device (U.S. Pat. No. 4,756,503) is disposed between the base arm of the lower rail and the bar of the upper rail so as to contact with a parallel portion of the base arm and a parallel portion of the bar. In the latter device, ear portions which upwardly extend from ends of the bar are encircled by inward portions which are inwardly folded from ends of the side arms so as to contact with the inward portions and the side arms through the projections of shoes which are attached on the ear portions. Play in the longitudinal direction and lateral direction of the upper rail relative to the lower rail is prevented by the contact of the roller and the contact of the shoes.
However, in the former seat slide device, when the upper rail is sliding, a slide resistance of the upper rail relative to the lower rail is increased, because the ear portions contact with the side arms and inward portion.
In the latter seat slide device, the number of component parts increases, because the device needs the roller and shoes.